Research on Microstructure Control Technology of Local Forming of Compressor Eccentric Shaft

According to the shape characteristics of a compressor eccentric shaft, the forging diagram was designed. The feasibility of local extrusion forming process for the eccentric shaft was verified by combining the numerical simulation and experiments. On the basis, the microstructure distribution of the eccentric forging formed at different temperatures was analyzed. It was found that the microstructure of the center of the forming zone is ferrite and pearlite, and the microstructure becomes coarse with the increase of forging temperature. The outer layer and the transition layer are mixed microstructure. In addition to ferrite and pearlite, bainite and tempered sorbite formed by self-tempering of low-temperature transformed martensite appear with the decrease of forming temperature. Moreover, the thickness of the mixed microstructure gradually increases with the decrease of forging temperature. The experiment shows that when the eccentric shaft forging is formed at 950 ℃, the thickness of the mixed microstructure of the transition layer and the outer layer is 1.9 mm, which is controlled within the range of mechanical turning. The microstructure of each part of the machined part is uniform, which can eliminate the heat treatment process after forging and does not affect the subsequent processing, reducing the processing costs.